Rustproofing coating



. Patented Nov. 28, 1,922.

STATES J'ERE SCANLLAN, OF DEARBOBN, AN'ID HENRY GARDNER, OF DETROIT,MICHIGAN.

RUSTZPROOFING COATING.

No Drawing.

To all tohomitmayconcemr Be -1t known that we,. Jenn. SOANLAN and HnnnxGARDNER, citizens of the United States, reslding at 133 Mason Streetnorth,

' Dearborn, and 2745 Third Avenue, Detroit,

a rust-proofing for metals and a method for accomplishing therust-proofing which is simple, and inexpensive while being, at the sametime, durable.

A further object of our invention is to provide a rust proof coating formetals, such as iron or steel, which will really prevent rust on thesurface of such metals so long asthe coating remains intact and which atthe same time will have a black or other color so that the metal may befinished over the rust proof coating with any. suitable coloring ofsiccative material. 0

A further object of our invention is to utilize a ,known method ofrust-proofing in combination with means for coloring such rust proofcoatingto conform to the color of the finish with which the metal is tobe coated. t i

With these and other zobjects in view, our invention consists in tfheprocess of forming the coating -and the coating itself as de; scribed inthis specification and set forth in the claims. I

In the practise of our invention we first coat the material to be rustproofed, such as iron or steel or any metal of a ferrous nature, withzinc or zinc alloy plating by any of the well known methods for formingsuch platings such for instance as by electrolysis. The method ofcoating or platlng the material with zinc will not be here moreparticularly described because it forms no part of the invention .inconnection with this application.

In connection with zinc plating, we believe that this type of rust proofcoating for ferrous metals is superior, in so far as prevent ing rust isconcerned, to any other typeof rust preventative coating. Zinc plating,

- however, is subject to the disadvantage that it cannot be successfullyenameled. or lacquered for use. in connection with metals which areexposed to the weather and which require a hlg fimsh such for instanceas an Application filed March 22, 1922. Serial No. 545,874.

tomobile parts. Where such coatings of varnish or the like are attemptedover -zinc plating a large number of such coatings are reuired in orderto give a pure black color to t e material and even then the coatingtends to chip off when it becomes thoroughly dry. In fact the enamelingof zinc plating, so far as we know, is conceded to be impracticable,

commercially.

After the material to be rust proofed has been so coated with the zincwe then subject it to a hot bath of an antimony solution which will formon the zinc a closely adhering metallic deposit of dead black or othercolor which can be given a very beautiful finish by simply applyingthereto one coat of enamel. I

By our invention we are, therefore, enabled to secure the well knownadvantages of the zinc plate rustproofing together with a .decrease inthe number of coats of enamel required to secure any desired finishon'the metal, thereby securing a durable and desirable finish for steelparts or for. ferrous parts which are to be exposed-to the weather andwhich require a high finish. v

In the practice of our process we have experimented with variousthicknesses of zinc plating with various solutions of antimony,

and with varioustimes for exposure of the plated article to theantimony: We were very successful in accomplishing our coating of thezinc plated article with the metal lic antimony by dipping articles intoa very hot solution of butter of antimony (antimony chloride diluted inthe 'proportion of one part, antimony chloride, British Pharmacopiastrength, to 1200' parts water). Where one pint'of the butter ofantlmony was used to 150 gallons of water, the water was brought to atemperature averaging the boiling point. Caustic sodato the amount oftwo pounds was added to this solution.

Our experiments show, however, that it is not necessary to use causticsoda, (NaOH) for an alkali in connection with this solution, as goodsuccess was obtained from potassium salts and more articularly frompotassium carbonate, (K 0 or from sodium hydroxide. Our experimentsfurther show that other salts ofantimony than antimony chloride SbCl andother salts which fall into the same class with antimony chloride,namely, arsenic, bismuth, and phosphorus, may be .used.--

In fact our invention consists in the col 45 more fully set forth as itis not our desire to oring of'the rust preventing zinc coating onvarious metals by means of some compound of the antimony group, an acidforming element such as chlorine and an alkaline solution.

The point of using the caustic soda or other alkali is to neutralize thedisintegrating effect of the acid used with the antimony compound, asthis acid tends to disintegrate the zinc coating thereby lessening itsrust proofing ability. Where, however, a slightly alkaline, neutral, ora very slightly acid solution of a salt of antimony is used, practicallyno disintegration of the zinc coating takes place, and a very evendeposit of metallic antimony may be formed on the zinc. The thickness ofthis deposit depends upon the relative proportion of antimony in thesolution and the length of time thatthe article is left in the solution.F orinstance, an article left in the solution made as described above,for approximately three minutes will have a very good coating ofmetallic antimony deposited thereon.

The advantages of our improved method of rust proofing are believed tohave been brought out in the main in the specification hereinafter, butit should be again pointed out that by our process we are enabled tosecure the advantages of the best rust proof coating with which we arefamiliar and at the same time we are enabled to provide a ferrousarticle with a very high finish with but very few coats or onesic-cative coating.

It will be understood that some variations may be made in theproportions of the solution herein described and that the temperaturemay be varied somewhat, changes in the proportions resulting, however,in correspending increases or decreases in the time for a coating to beformed, and changes in the heat of the solution resulting similarly.Different salts of antimony will be used also to give colors other thanblack. These coatmgs, however, of other colors are not herein cover bythis application any particular method of coating ferrous material toobtain any color other than black as each such color is obtained byvarying the salt of antimony used, so that we desire to cover themethods of obtaining the specific colors separately, and to cover themethod of producing the black, and the method generally, in thisapplication.

What we claim is:

1. The method of coating the surfaces of ferrous articles for rustproofing consisting of first plating such surfaces with zinc or zinccompounds and then depositing metallic antimony on the plated surfaces.

2. The method of coating the surfaces of ferrous articles for rustproofing consisting of first plating the articles with zinc or zinccompounds, then coating the plated surface with metallic antimony, andcoating the surface thus formed with a siccative coating.

3. The method of rust proofing ferrous surfaces consisting of firstplating the surface with zinc or zinc compounds and then subjecting theplated surface to the action of a solution of antimony chloride.

4. The method of rust proofing ferrous surfaces consisting of firstplating such surfaces with zinc or zinc compounds and then subjectingthe plated surfaces to the action of a hot solution of a salt ofantimony and a forming acid.

5. The method of rust proofing a ferrous surface consisting of firstcoating the surface with zinc then subjecting it to a solution of a saltof antimony and a forming acid, and then coating the 6. The method ofrust proofing ferrous surfaces consisting of zinc plating such surfacesand then subjecting them to a hot bath formed from a solution of a saltof antimony, a forming acid, and an alkali.

7. The method of rust surface consisting of zinc plating the surface andthen subjecting it to the action of a hot solution of a salt ofantimony, an acid, and sufficient alkali to render the solution nearneutral.

8. The method of rust proofing of ferrous surfaces consisting of zincplating such surfaces and then subjecting the plated surfaces to asubstantially neutralized acid solution of a salt of antimony;

proofing ferrous surface thus formed with a .siccative coating. 4

9. The method of coating ferrous surfaces for rust proofing consistingof zinc plating the surfacesand then subjecting them to a hot bathformed from a solution of'a salt of antimony, an acid, and potassiumsalts.

10. The method of rust proofing ferrous surfaces consisting of zincplating the surfaces and then subjecting them to a solution of antimonychloride and caustic soda 1n substantially the proportions of one pintof antimony chloride, two pounds of caustic soda, and one hundred andfifty gallons of water.

11. The method of rust proofing of ferrous surfaces consisting of zincplating such surfaces and then subjecting the plated surfaces to asubstantially neutralized acid so lution of a salt of antimonysubstantially in the proportions specified.

February 6, 1922.

J ERE SCANLAN. HENRY GARDNER.

